Transfer mold manufacturing method, transfer mold manufactured thereby, and component produced by the transfer mold

ABSTRACT

A transfer mold, which has superior durability and high aspect ratio, for production of a component by electroplating and a component produced thereby are provided. A method therefor includes the steps of forming a resist pattern having a shape of a component with a desired aspect ratio on a metal substrate, a sidewall of the resist pattern forming a desired angle, creating a transfer mold by filing up the resist pattern having the shape of the component by electroplating to a predetermined thickness and providing a master mold by separating the transfer mold from the metal substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No.PCT/JP2011/006355 having International filing date 15 Nov. 2011, whichdesignated the United States of America, and which InternationalApplication was published under PCT Article 21 (s) as WO Publication2013/072953 A1 the disclosures of which are incorporated herein byreference in their entireties.

BACKGROUND

The presently disclosed embodiment relates to a transfer moldmanufacturing method, a transfer mold manufactured thereby, and acomponent produced by the transfer mold. More specifically, thepresently disclosed embodiment relates to a method for manufacturing atransfer mold for production of a component by electroplating, atransfer mold manufactured thereby, and a component produced thereby,wherein the transfer mold has superior durability and high aspect ratio.

Electroplating allows formation of a thick film conductor with lessrestriction in terms of dimension. It is therefore widely used inproduction of display components such as a dial and hands of a watch,machine components such as a small gear, a spring, a pipe and adiaphragm (pressure sensor) and electronic components such as a wiringof a semiconductor device and a coil.

Japanese Patent Application Laid-Open No. 2004-1535 disclosesmanufacturing a cavity insert by: first creating a machined master moldon which a fine pattern has been formed in advance; subsequentlycreating a transfer master mold by hot press from the machined mastermold; and then creating the cavity insert by electroplating from thetransfer master mold.

Japanese Patent Application Laid-Open No. 2004-257861 disclosesmanufacturing a watch dial by the steps of: forming a mask patternhaving openings on a surface of a silicon wafer; performing ananisotropic etching; forming a common electrode film; forming anelectroplated film which grows on the common electrode film; etching thesilicon wafer; and forming a resin watch dial having protruding portionsby using the electroplated film as a transfer mask.

FIGS. 6 a and 6 b show structural drawings of a component formed byusing a conventional transfer mold. In FIG. 6 a, for the purpose offorming a component 95, a photoresist 30 is patterned on a metalsubstrate 90 to a shape of the component by partially removing the same.The metal substrate 90, on which the resist pattern has thus beenformed, is used as a transfer mold for electroplating (hereinafterreferred to as “EP”) a predetermined metal (Ag, Cu, Ni, etc.) to formthe component 95.

In FIG. 6 b, the component 95 molded by EP is transferred onto anadhesive bond 85 and then adhered to a component substrate 97. In thismanner, the component having a given shape depending on its intended useis produced by EP and transferred onto the component substrate 97 foruse.

Here, for ease of release and transfer of the component 95, the angles βformed at sidewalls of the photoresist 30 are each set to be a bluntangle of less than 45°. In the meantime, when providing an electroniccomponent such as a wiring, a coil, etc. on a semiconductor substrate,there is a demand for such an aspect ratio that a line thickness isgreater than the line width so that electric resistance is reduced. Thethickness which the photoresist 30 is generally required to have isapproximately 10 μm.

The component 95 is formed by EP in such a manner that it fills up alongthe sidewalls of the photoresist 30 having the thickness ofapproximately 10 μm. As such, in a case where a wiring pattern, aconductive coil or the like is formed as a long component, it contactsthe sidewalls in large area, resulting in increased release resistancein the release and transfer of the component. That is, when using atransfer mold made with patterned photoresist, the transfer of thecomponent onto the component substrate 97 requires an application of arelease force that is comparable to the increased release resistance.This causes the edge of the pattern of the photoresist 30, which isappressed to the metal substrate 90, to be easily stripped. In fact, theresist is stripped after a few times of use, and as a result, a problemarises that the transfer mold can then no longer be in use.

SUMMARY

The presently disclosed embodiment has been made in order to solve theabove problem, and its purpose is to provide a transfer mold havingsuperior durability and high aspect ratio for production of a componentby EP as well as to provide a component produced by the transfer mold.It is to be noted that there are four types of transfer molds which are:a master mold, a mother mold, a son mold, and a transfer mold. Themaster mold is a mold which serves as a prototype for componentproduction. Usually, it is not directly used for component production.The mother mold is a mold which is created by using the master mold soas to have an inverse contour of the master mold. The mother mold aswell is not directly used for the component production. The son mold isa mold which is created by using the mother mold so as to have aninverse contour of the mother mold. Therefore, the son mold has a shapethat is identical with the master mold. The transfer mold is generallyformed by subjecting the son mold to an insulation layer formationprocess, a releasing layer formation process, etc. The componentproduction is then carried out with use of this transfer mold, and whenit is worn off, a new transfer mold is created again from the mastermold by way of the mother mold and the son mold.

A transfer mold manufacturing method of the presently disclosedembodiment includes steps of: forming a resist pattern having a shape ofa component with a desired aspect ratio on a metal substrate, a sidewallof the resist pattern on a metal substrate side forming a desired angleα (α<90°); filling up the resist pattern having the shape of thecomponent by electroplating to a predetermined thickness and thenseparating a mold thus formed from the metal substrate leaving the metalsubstrate and the resist pattern.

A transfer mold manufacturing method of the presently disclosedembodiment includes steps of: forming a resist pattern having a shape ofa component with a desired aspect ratio on a metal substrate, a sidewallof the resist pattern on a metal substrate side forming a desired angleα (α<90°); filling up the resist pattern having the shape of thecomponent by electroplating to a predetermined thickness and thenproviding a master mold by separating a mold thus formed from the metalsubstrate leaving the metal substrate and the resist pattern; creating ason mold by transferring by way of the master mold and a mother mold;and providing a transfer mold by performing, on the son mold, areleasing layer formation process for facilitating a release of thecomponent to be formed by electroplating and an insulation layerformation process for forming an insulation layer in that portion whichis other than a portion in which the component is to be formed.

The transfer mold manufacturing method of the presently disclosedembodiment includes a step of forming a roughening layer on a surface ofthe metal substrate as a first step.

A transfer mold manufacturing method of the presently disclosedembodiment includes steps of: forming a resist pattern having a shape ofa component with a desired aspect ratio on a metal substrate side, asidewall of the resist pattern on a metal substrate side forming anangle of approximately 90°; filling up the resist pattern having theshape of the component by electroplating to a predetermined thicknessand then separating a mold thus formed from the metal substrate leavingthe metal substrate and the resist pattern; removing a photoresistpartially to leave a resist pattern layer in that portion of theseparated mold which is other than a portion corresponding to thecomponent to be transferred; and treating the sidewall of the shape ofthe component with beam irradiation using the resist pattern layer as aprotective layer, the beam irradiation being modulated such that theangle at the sidewall is tailored to form approximately 90° or a desiredangle α (α<90°).

A transfer mold manufacturing method of the invention of the instantapplication includes steps of: forming a resist pattern having a shapeof a component with a desired aspect ratio on a metal substrate, asidewall of the resist pattern on a metal substrate side forming anangle of approximately 90°; filling up the resist pattern having theshape of the component by electroplating to a predetermined thicknessand then separating a mold thus formed from the metal substrate leavingthe metal substrate and the resist pattern; removing a photoresistpartially to leave a resist pattern layer in that portion on theseparated mold which is other than a portion corresponding to thecomponent to be transferred; providing a master mold by treating thesidewall of the shape of the component with beam irradiation using theresist pattern layer as a protective layer, the beam irradiation beingmodulated such that the angle at the sidewall is tailored to formapproximately 90° or a desired angle α (α<90°); creating a son mold bytransferring by way of the master mold and a mother mold; and providinga transfer mold by performing, on the son mold, a releasing layerformation process for facilitating a release of the component to beformed by electroplating and an insulation layer formation process forforming an insulation layer in that portion which is other than aportion in which the component is to be formed.

The method of the presently disclosed embodiment includes a step offorming a roughening layer on a surface of the metal substrate as afirst step.

A transfer mold of the presently disclosed embodiment is manufactured bythe above-described method and has a cross-sectional surface with adesired aspect ratio, a sidewall of the cross-sectional surface formingan angle between 45° and 88°.

A transfer mold of the presently disclosed embodiment is provided bysubjecting the son mold created by using the above-described master moldto only an insulation layer formation process or to the insulation layerformation process and a releasing layer formation process.

A component produced by electroplating in the presently disclosedembodiment is molded by the electroplating using the above-describedtransfer mold and transferred.

The presently disclosed embodiment makes it possible to provide acomponent having superior durability and high aspect ratio formed by EPin manufacturing display components, machine components and electroniccomponents by EP.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a-1 e are process drawings showing the steps for manufacturing amaster mold by electroplating according to the presently disclosedembodiment.

FIGS. 2 a-2 d are process drawings showing the steps for manufacturing amaster mold by beam treatment according to the presently disclosedembodiment.

FIGS. 3 a-3 c are process drawings showing the steps for manufacturing ason mold according to the presently disclosed embodiment.

FIGS. 4 a-4 f are process drawings showing the steps for manufacturing atransfer mold according to the presently disclosed embodiment.

FIGS. 5 a-5 c are process drawings showing the steps for manufacturing acomponent according to the presently disclosed embodiment.

FIGS. 6 a and 6 b are structural drawings showing a component formed byusing a conventional transfer mold.

DETAILED DESCRIPTION

A first aspect of the presently disclosed embodiment is described withreference to the drawings. FIGS. 1 a-1 e are process drawings showingthe steps for manufacturing a master mold by electroplating according tothe presently disclosed embodiment. In FIG. 1 a, a top surface of ametal substrate 10 is provided with a roughening layer 15 for rougheninga contact surface of a master mold to be formed by EP. The rougheninglayer 15 may be formed by roughening the surface of the metal substrate10 directly by hydrochloric acid treatment or the like. Alternatively, astripe-like photo resist pattern layer, a lattice-like photo resistpattern layer or the like, which is suitable for roughening, may beformed as the roughening layer 15 by partially removing the photoresist.In a case where an insulation layer and others are formed on a son mold60 described later with reference to FIGS. 3 a-3 c, the roughening layer15 may be omitted as long as there is no problem of adhesion strengththerebetween.

In FIG. 1 b, a photoresist 30 for forming a pattern of a shape of acomponent to be produced is applied onto the roughening layer 15 on themetal substrate 10 to a predetermined thickness. This is for the purposeof obtaining a component having such a shape that has a desired aspectratio and desired angles α at sidewalls thereof. For example, in a casewhere a wiring of a semiconductor electronic component or a coil with aline width of 5 μm is to be produced, the photoresist 30 is applied to athickness of 10 μm so that the electronic component or the coil has thethickness of 10 μm. The photoresist 30 is then subjected to an exposureeffected from the direction of the arrows with an intervening photomask40 having a pattern of a desired component. FIG. 1 c shows the patternof the component formed by subjecting the resist pattern to the exposureas shown in FIG. 1 b and a development. The angles α formed at therespective sidewalls of the resist pattern of the component canoptionally be determined depending on the material and film thickness ofthe applied photoresist 30 as well as the exposure condition to theirradiation performed with the intervening photomask 40 as shown in FIG.1 b. Where laser light is used, a 3D lens may be employed to vary theirradiation intensity on the both sidewalls of the resist pattern. Theirradiation intensity on the both sidewalls may also be varied by meansof a gray mask.

In FIG. 1 d, a desired metal, e.g., Ni, is electroplated to apredetermined thickness so as to cover the resist pattern 30 shown inFIG. 1 c, thereby creating a master mold 20. In FIG. 1 e, the mastermold 20 created by EP in FIG. 1 d is separated from the metal substrate10. Here, the rough surface profile of the roughening layer 15 has beentransferred to a roughened surface layer 17 of the master mold. Theangles α at the both sidewalls remain to be the angles α in FIG. 1 d.

It is intended that the roughened surface layer 17 of the master mold istransferred to the son mold 60, which is eventually used as the transfermold and illustrated in FIG. 3, for the sake of increased adhesionstrength to an insulation layer to be formed thereon. As such, it is notnecessarily required. In addition, making the angles α as acute as 45°to 88° allows the pattern density of an intended device to be improved.The 10 μm thickness of the photoresist 30 in FIG. 1 c is maintained inthe inverted master mold 20 by being transferred.

FIGS. 2 a-2 d are process drawings showing the steps for manufacturing amaster mold by beam treatment according to the presently disclosedembodiment. This is a second aspect of the presently disclosedembodiment. FIG. 2 a shows the master mold 20 created by the methodillustrated in FIGS. 1 a-1 e. Here, the angles α are each approximately90°. In FIG. 2 b, the photoresist 30 for forming a reverse pattern ofthe shape of the component is applied to a predetermined thickness. Thephotoresist 30 is then subjected to an exposure effected from thedirection of the arrows with an intervening photomask 40 having thereverse pattern of the component. As a result, that portion of theresist which corresponds to the component is developed and removed,thereby leaving the photoresist 30 only on the flat roughened surfacelayer 17 of the master mold.

In FIG. 2 c, the resist pattern formed in FIG. 2 b is used as aprotective film in treating the sidewalls of the pattern of thecomponent with beam irradiation. Here, the irradiation beam is modulatedin such a manner that the angles α are tailored to form predetermineddegrees. The arrows show the direction of the beam. The treated mastermold 20 shown in FIG. 2 d has not only the same shape but also the samefunction and characteristics as the master mold 20 shown in FIG. 1 d.The irradiation beam may be an electron beam, an ion beam, or a FIB(Focused Ion Beam) whose irradiation strength is variable by focusingthe beam with a lens.

FIGS. 3 a-3 c are process drawings showing the steps for manufacturing ason mold according to the presently disclosed embodiment. In FIG. 3 a, adesired metal, e.g., Ni, is electroplated to a predetermined thicknesson that surface of the master mold 20 manufactured in FIGS. 1 a-1 e or 2a-2 d on which the pattern of the component has been formed. A mothermold 50 created thereby is then separated. In FIG. 3 b, a desired metal,e.g., Ni, is electroplated to a predetermined thickness on that surfaceof the mother mold 50 on which the pattern of the component has beenformed, so that a son mold 60 is created in the same manner. In FIG. 3c, the son mold 60 thus created by EP is separated from the mother mold50.

In this way, the son mold 60 is created by transferring the mother mold50 created by transferring the master mold 20. As such, it takes overthe same function and characteristics as those of the master mold 20.Furthermore, the son mold 60 is integrally formed of one metal material.This, with the releasing layer formation process and the insulationlayer formation process performed on a roughened surface layer 19 of theson mold as will be explained next, makes it possible to obtain atransfer mold which has a desired aspect ratio and angles α, does notbreak even after repetitive use, and is highly suitable for quantityproduction.

FIGS. 4 a-4 f are process drawings showing the steps for manufacturing atransfer mold according to the presently disclosed embodiment. FIG. 4 ashows the son mold 60 created in FIG. 3 c. In FIG. 4 b, the son mold 60is subjected to heat treatment under prescribed conditions for ease ofrelease and transfer of the component to be produced. This is followedby the releasing layer formation process for forming a NiOx film 70having a predetermined thickness on the surface of the son mold 60.Since the NiOx film 70 is conductive, it does not hinder EP. Moreover,the low adhesive property thereof to the electroplated component allowsan easy release.

Subsequently, an insulation layer is formed in order to prevent EP inthat portion of the surface which is other than the portion in which thecomponent is to be formed. This is accomplished by the insulation layerformation process for forming a SiO₂ film 80 chemically by CVD (ChemicalVapor Deposition) or physically by sputtering on said portion of thesurface. Alternatively, the SiO₂ film 80 is formed by applyingpolysilazane and treating it with heat. In FIG. 4 c, in order to removethe SiO₂ film 80 formed on the pattern of the component, the photoresist30 to be patterned to a predetermined shape is applied on the SiO₂ film80. After that, the photoresist is partially removed by subjecting thesame to an exposure effected from the direction of the arrows with anintervening photomask 40 having the reverse pattern of the component.Then, in FIG. 4 d, with use of the patterned photoresist 30 as a mask,the SiO₂ film 80 is removed physically by beam irradiation from thedirection of the arrows or chemically by hydrofluoric acid treatment orthe like.

Depending on the shape of the patterned photoresist 30 and the removalconditions of the SiO₂ film 80, the transfer mold is completed either byremoving the SiO₂ film 80 only in the bottom portion so that it is lefton the sidewalls as shown in FIG. 4 e or by removing the SiO₂ film 80both on the sidewalls and in the bottom portion as shown in FIG. 4 f. Ina case where polysilazane is used, similar steps as in screen printingare carried out. That is, following the formation of the NiOx film inFIG. 4 b, polysilazane is printed in that portion of the surface of theNiOx film 70 which is other than the pattern of the component forforming the component. It is then treated with heat. In this manner, thesame shape as shown in FIG. 4 f can be obtained.

The releasing layer formation process is performed by, as shown in FIG.4 b, depositing metal oxides (AlOx, TiOx, etc.), nitrides or organicsubstances (resist) on the son mold 60 to such a thickness of 1 to 1000Å that allows the conductivity thereof to be maintained. For theinsulation layer formation process, an insulator such as resist may beused instead of SiO₂. Note that the releasing layer formation processand the insulation layer formation process may be performed in reverseorder.

Now, description is made for the component produced by EP with use ofthe transfer mold according to the presently disclosed embodiment. FIGS.5 a-5 c are process drawings showing the steps for manufacturing acomponent using the transfer mold according to the presently disclosedembodiment. In FIG. 5 a, a desired metal (Ag, Cu, Ni, etc.) iselectroplated on the son mold 60 to form the component 95. In FIG. 5 b,the component 95 molded by EP is, as in the case shown in FIG. 6 b,transferred onto the adhesive bond 85 and then adhered to the componentsubstrate 97. Alternatively, the component 95 is adhered to a greensheet 98 which is then treated with heat for curing. Where the component95 is adhered to the green sheet 98, the use of the adhesive bond 85 iseliminated by such softness of the green sheet 98 before curing that thecomponent 95 is buried therein. In this way, the component 95 of anoptional shape having a desired aspect ratio and angles α is provided byEP. It can be repetitively molded and transferred onto the devicesubstrate 97 or green sheet 98 for diverse intended use.

As described above, the presently disclosed embodiment is able toprovide a component having superior durability and high aspect ratio inproduction, by EP, of display components such as a dial and hands of awatch, machine components such as a small gear, a spring, a pipe and adiaphragm (pressure sensor), and electronic components such as a wiringof a semiconductor device and a coil.

DESCRIPTION OF REFERENCE NUMERALS

-   10 metal substrate-   15 master mold roughening layer-   17 roughened surface layer of master mold-   18 roughened surface layer of mother mold-   19 roughened surface layer of son mold-   20 master mold-   30 photoresist-   40 photomask-   50 mother mold-   60 son mold-   70 NiOx-   80 SiO₂/polysilazane-   85 adhesive bond-   90 metal substrate-   95 component-   97 component substrate-   98 green sheet-   α angle at sidewall-   β angle at sidewall

1. A transfer mold manufacturing method comprising steps of: forming aresist pattern having a shape of a component with a desired aspect ratioon a metal substrate, a sidewall of the resist pattern on a metalsubstrate side forming a desired angle α less than 90°; filling up theresist pattern having the shape of the component by electroplating to apredetermined thickness and then separating mold thus formed from themetal substrate leaving the metal substrate and the resist pattern.
 2. Atransfer mold manufacturing method comprising steps of: forming a resistpattern having a shape of a component with a desired aspect ratio on ametal substrate, a sidewall of the resist pattern on a metal substrateside forming a desired angle α (α<90°); filling up the resist patternhaving the shape of the component by electroplating to a predeterminedthickness; and then providing a master mold by separating a mold thusformed from the metal substrate leaving the metal substrate and theresist pattern; creating a son mold by transferring by way of the mastermold and a mother mold; and providing a transfer mold by performing, onthe son mold, a releasing layer formation process for facilitating arelease of the component to be formed by electroplating and aninsulation layer formation process for forming an insulation layer inthat portion which is other than a portion in which the component is tobe formed.
 3. The method according to claim 1, comprising a step offorming a roughening layer on a surface of the metal substrate as afirst step.
 4. A transfer mold manufacturing method comprising steps of:forming a resist pattern having a shape of a component with a desiredaspect ratio on a metal substrate, a sidewall of the resist pattern on ametal substrate side forming an angle of approximately 90°; filling upthe resist pattern having the shape of the component by electroplatingto a predetermined thickness and then separating a mold thus formed fromthe metal substrate leaving the metal substrate and the resist pattern;removing a photoresist partially to leave a resist pattern layer in thatportion on the separated mold which is other than a portioncorresponding to the component to be transferred; and treating thesidewall of the shape of the component with beam irradiation using theresist pattern layer as a protective layer, the beam irradiation beingmodulated such that the angle at the sidewall is tailored to formapproximately 90° or a desired angle α less than 90°.
 5. A transfer moldmanufacturing method comprising steps of: forming a resist patternhaving a shape of a component with a desired aspect ratio on a metalsubstrate, a sidewall of the resist pattern on a metal substrate sideforming an angle of approximately 90°; filling up the resist patternhaving the shape of the component by electroplating to a predeterminedthickness and then separating a mold thus formed from the metalsubstrate leaving the metal substrate and the resist pattern; removing aphotoresist partially to leave a resist pattern layer in that portion onthe separated mold which is other than a portion corresponding to thecomponent to be transferred; providing a master mold by treating thesidewall of the shape of the component with beam irradiation using theresist pattern layer as a protective layer, the beam irradiation beingmodulated such that the angle at the sidewall is tailored to formapproximately 90° or a desired angle α less than 90°; creating a sonmold by transferring by way of the master mold and a mother mold; andproviding a transfer mold by performing, on the son mold, a releasinglayer formation process for facilitating a release of the component tobe formed by electroplating and an insulation layer formation processfor forming an insulation layer in that portion which is other than aportion in which the component is to be formed.
 6. The method accordingto claim 4, comprising a step of forming a roughening layer on a surfaceof the metal substrate as a first step.
 7. A transfer mold manufacturedby the method according to claim 1 having a cross-sectional surface witha desired aspect ratio, a sidewall of the cross-sectional surfaceforming an angle between 45° and 88°.
 8. A transfer mold manufactured bythe method according to claim
 2. 9. A component produced byelectroplating, the component being molded by the electroplating usingthe transfer mold according to claim 8 and transferred.